Since there are only 32 numbers to try: 02, 12, 22, 32, ..., 312 (322 is larger than 1000), it would be easiest just to try them all.
However, if you want a little more orgainized way, you might consider this:
What is the result when the
-- one's digit is a 1? 1
-- one's digit is a 2? 4 x
-- one's digit is a 3? 9
-- one's digit is a 4? 6
-- one's digit is a 5? 5
-- one's digit is a 6? 6
-- one's digit is a 7? 9
-- one's digit is an 8? 4 x
-- one's digit is a 9? 1
So the question becomes: How many numbers smaller than 32 have a one's digit which is either a "2" or an "8"?